Question: What galaxy cluster has the most flux?
Paraphrase: Which galaxy cluster has the most density?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q204107 . ?ent wdt:P2221 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: Coma Cluster, Centaurus Cluster, Abell 1689, Leo Cluster